DArT whole genome profiling provides insights on the evolution and taxonomy of edible Banana (Musa spp.).

BACKGROUND AND AIMS: Dessert and cooking bananas are vegetatively propagated crops of great importance for both the subsistence and the livelihood of people in developing countries. A wide diversity of diploid and triploid cultivars including AA, AB, AS, AT, AAA, AAB, ABB, AAS and AAT genomic constitutions exists. Within each of this genome groups, cultivars are classified into subgroups that are reported to correspond to varieties clonally derived from each other after a single sexual event. The number of those founding events at the basis of the diversity of bananas is a matter of debate. METHODS: We analysed a large panel of 575 accessions, 94 wild relatives and 481 cultivated accessions belonging to the section Musa with a set of 498 DArT markers previously developed. KEY RESULTS: DArT appeared successful and accurate to describe Musa diversity and help in the resolution of cultivated banana genome constitution and taxonomy, and highlighted discrepancies in the acknowledged classification of some accessions. This study also argues for at least two centres of domestication corresponding to South-East Asia and New Guinea, respectively. Banana domestication in New Guinea probably followed different schemes that those previously reported where hybridization underpins the emergence of edible banana. In addition, our results suggest that not all wild ancestors of bananas are known, especially in M. acuminata subspecies. We also estimate the extent of the two consecutive bottlenecks in edible bananas by evaluating the number of sexual founding events underlying our sets of edible diploids and triploids, respectively. CONCLUSIONS: The attribution of clone identity to each sample of the sets allowed the detection of subgroups represented by several sets of clones. Although morphological characterization of some of the accessions is needed to correct potentially erroneous classifications, some of the subgroups seem polyclonal.

MGIS: managing banana (Musa spp.) genetic resources information and high-throughput genotyping data.

Database URL: https://www.crop-diversity.org/mgis/.

Evolution of cassava (Manihot esculenta Crantz) after recent introduction into a South Pacific Island system: the contribution of sex to the diversification of a clonally propagated crop.

Cassava (Manihot esculenta Crantz) is a clonally propagated crop that was introduced into the South Pacific archipelago of Vanuatu in the 1850s. Based on a survey conducted in 10 different villages throughout the archipelago, we present here a study of its diversity. Farmers' knowledge about cultivation cycle and sexual reproduction of cassava was recorded during group interviews in each village. Using a set of 11 SSR markers, we genotyped the 104 landraces collected and 60 supplementary accessions from a within-landrace study (12 landraces x 5 plants). Out of the 104 landraces collected, we discovered 77 different multilocus genotypes and the within-landrace study identified several polyclonal landraces. Our data suggest a number of hypotheses about the dynamics of diversity of cassava in Vanuatu.

Prostheses for persons with lower-limb amputations: an extra joint increases range of motion.

This report describes two cases in which the addition of an extra joint enhanced range of motion and improved function in persons with unilateral lower-limb amputation. Both individuals had significant disability in the workplace and at home before this modification. In the first case, an individual with a hemipelvectomy had inadequate hip-joint flexion for maneuvering during photo shoots. In the second case, the individual's transfemoral prosthesis provided insufficient knee flexion for kneeling and working in tight spaces. In each case, a manual-locking, single-axis knee joint was added adjacent to the joint with the limited range of motion. In both cases, the addition of the second joint provided the increased flexibility needed. The first person's hip-flexion range improved from 125 degrees to 190 degrees, and the second person's knee-flexion range improved from 140 degrees to 170 degrees. In repeated follow-up, both patients remained highly satisfied with the intervention. The addition of an extra joint is an option that should be considered when inadequate range interferes with function.